1. Field of the Invention
Aspects of the invention relate to a method and an apparatus to handover a mobile node between heterogeneous networks, and, more particularly, to a method and an apparatus to handover a mobile node between heterogeneous networks, in which information regarding a network of a mobile node is provided to a correspondent node to allow the correspondent node to transmit data in a form that is suitable to the network capacity of the mobile node.
2. Description of the Related Art
With the widespread use of mobile terminals, such as notebook computers and personal digital assistants (PDAs), increased attention has been focused on developing ways of using the Internet at various locations. In particular, research has been directed to providing seamless communication without disruption of service while moving from one to another subnet. In this regard, a mobile internet protocol (IP) technique is a representative example of techniques indicating IP mobility.
Mobile terminals having mounted therein various interfaces, such as a wireless local area network (LAN) interface, a code division multiple access (CDMA) interface, and an Ethernet interface are on the market, and it is expected that mobile terminals having mounted therein wireless broadband (WiBro) and other wired/wireless interfaces will likely emerge in the future. Also, in the same wireless LAN (WLAN), there are typically various standards in use, such as the (Institute of Electrical and Electronics Engineers (IEEE)) IEEE802.11b standard supporting the data rate of 11 Mbps and the IEEE802.11a and IEEE802.11g standards supporting the data rate of 54 Mbps. Further, a method of using a mobile IP has been developed to allow free movement between wireless networks.
FIG. 1 illustrates a handover process between heterogeneous networks according to a conventional mobile IP technique. Referring to FIG. 1, there is a network including a transmitter (correspondent node) 20 transmitting continuous data to a mobile node 10 and a wireless LAN (IEEE 802.11g) network including the mobile node 10. A CDMA network covers an area including the wireless LAN network.
When a mobile node user is moving while receiving traffic data at 10 Mbps from the correspondent node 20, the mobile node user can move out of service range of IEEE 802.11g.wireless LAN. At this time, the mobile node user can continue to receive service in another way and can use CDMA, which has a wider service range, but is expensive and has a low transfer rate. Session interruption during movement of the mobile node user can be prevented using a mobile IP, and a method of preventing such session interruption is under development.
Referring to FIG. 1, the mobile node 10 requests data from the correspondent node 20 and continuously receives data from the correspondent node 20 at a rate of 10 Mbps through an IEEE 802.11 network. Where the mobile node 10 moves in a downward direction while continuously receiving data and moves out of a service range of the IEEE 802.11g wireless LAN, a CDMA network can take over a communication session using a mobile IP for seamless service. Upon completion of a handover, the data transmitted from the correspondent node 20 is transferred to the mobile node 10 through the CDMA network.
However, in FIG. 1, the amount of data transmitted from the correspondent node 20 is typically larger than the amount of data that can be serviced by the CDMA network. In this regard, since a maximum data rate supported by the CDMA network is 2.4 Mbps, the amount of data actually transmitted is only 2.4 Mbps out of the data transmitted from the correspondent node 20, such as 10 Mbps, suggesting occurrence of a possible data loss of 7.6 Mbps. In other words, although a session is taken over using a mobile IP, a normal communication service typically cannot be provided.
The Internet tends to transmit as much data as possible by fully using an available network (best effort service). Such a tendency to transmit as much data as possible is typically true in a multimedia service to provide superior audio quality and display quality. However, due to increasing numbers of heterogeneous wireless networks having different capacities, it can be difficult to provide a smooth service due to differences between infrastructures of applications tending to transmit as much data as possible and wireless networks limiting their available bandwidths differently.
For example, a method of handover between heterogeneous networks using a mobile IP is disclosed in Korean Patent Publication No. 2004-49125. In this regard, Korean Patent Publication No. 2004-49125 discloses an apparatus and method for handover between different mobile communication systems.